US2903326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Improved process for bleaching cellulose pulp using chlorate
Assignee: Pennwalt Corp
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Filing: 1956-10-17
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Granted: 1959-09-08
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Expires: 1976-10-17
Abstract
No abstract record available.
Inventors
- 👤 Joseph B Heitman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:26
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/12; D21C9/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
128 words
IN A CONVENTIONAL COMMERCIAL PROCESS FOR BLEACHING CELLULOSE PULP COMPRISING THE STEP OF CONTACTING AN AQUEOUS SUSPENSION OF SAID PULP WITH CHLORINE IN AT LEAST ONE STAGE OF SAID PROCESS AT A PH IN THE RANGE FROM ABOUT 2 TO BELOW 7 AND AT A TEMPERATURE IN THE RANGE FROM ABOUR 0* C. TO ABOUT 50* C., THE IMPROVEMENT WHICH CONSISTS OF CARRYING OUT SAID CONTACTING IN FURTHER CONTACT WITH FROM ABOUT 0.01% TO ABOUT 5% O F AN ADDED AMOUNT OF AN INORGANIC CHLORATE SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL CHLORATES, ALKALINE EARTH METAL CHLORATES AND CHLORIC ACID BASED ON THE WEIGHT OF SAID PULP FOR A PERIOD OF TIME AT LEAST SUFFICIENT TO SOLUBILIZE A SUBSTANTIAL PORTION OF COLORED LIGNIN MATERIALS IN SAID CELLULOSE.
Claim 2
Dependent Claim
128 words
IN A CONVENTIONAL COMMERCIAL PROCESS FOR BLEACHING CELLULOSE PULP COMPRISING THE STEP OF CONTACTING AN AQUEOUS SUSPENSION OF SAID PULP WITH CHLORINE IN AT LEAST ONE STAGE OF SAID PROCESS AT A PH IN THE RANGE FROM ABOUT 2 TO BELOW 7 AND AT A TEMPERATURE IN THE RANGE FROM ABOUR 0* C. TO ABOUT 50* C., THE IMPROVEMENT WHICH CONSISTS OF CARRYING OUT SAID CONTACTING IN FURTHER CONTACT WITH FROM ABOUT 0.01% TO ABOUT 5% O F AN ADDED AMOUNT OF AN INORGANIC CHLORATE SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL CHLORATES, ALKALINE EARTH METAL CHLORATES AND CHLORIC ACID BASED ON THE WEIGHT OF SAID PULP FOR A PERIOD OF TIME AT LEAST SUFFICIENT TO SOLUBILIZE A SUBSTANTIAL PORTION OF COLORED LIGNIN MATERIALS IN SAID CELLULOSE.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-09-07 | 1963-03-09 | 1963-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-09-07 | 1967-03-09 | 1967-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-09-07 | 1971-03-09 | 1971-09-08 | $7700.00 | Window Closed / Lapsed |